1. Field of the Invention
This invention relates to a process for beneficiating phosphate ore, and, more particularly, to a process by which phosphate ore can be beneficiated with improved recovery in the cationic floatation step.
2. Description of the Prior Art
A standard method for the beneficiation of phosphate ore is called "double float". The phosphate ore is first floated with any of one or more of several well-known anionic reagents (i.e., fatty acids), which leaves the rougher tailings low in phosphate values. This "single float" product still contains some silica, which is then scrubbed with sulfuric acid to remove the reagents and then subjected to floatation using any of one or more of several well-known cationic reagents (i.e., amines). The majority of the remaining silica is floated away, leaving a "double float" product high in phosphate values and very low in silica. The tailings (i.e., silica component) from the amine floatation still contain more phosphate values than is desireable to discard as waste, but the values are not great enough to be utilized as a product.
I have now discovered that it is possible to recover approximately two-thirds of the phosphate values that were previously lost in the amine tailings.
These lost phosphate values are recovered by modifying the standard "double float" process to a "triple float" process by removing the tailings in the amine float in two stages instead of one, and, surprisingly, this is accomplished with approximately the same volume of amine reagent currently utilized in the "double float" process.